Information handling system stylus body with flexible button actuator

ABSTRACT

An information handling system stylus includes components to support active tip writing inputs at a touchscreen display controller by buttons integrated in the stylus housing as a thin material formed contiguous with the stylus housing material. A leaf spring biases upwards at the button thin material and has a magnet coupled to it that, upon a press at the button, is detected as increased magnetic flux by a magnetic sensor disposed under the leaf spring.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates in general to the field of portableinformation handling systems, and more particularly to an informationhandling system stylus body with flexible button actuator.

Description of the Related Art

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Portable information handling systems integrate processing components, adisplay and a power source in a portable housing to support mobileoperations. Portable information handling systems allow end users tocarry a system between meetings, during travel, and between home andoffice locations so that an end user has access to processingcapabilities while mobile. Tablet configurations typically expose atouchscreen display on a planar housing that both outputs information asvisual images and accepts inputs as touches. Convertible configurationstypically include multiple separate housing portions that couple to eachother so that the system converts between closed and open positions. Forexample, a main housing portion integrates processing components and akeyboard and rotationally couples with hinges to a lid housing portionthat integrates a display. In a clamshell configuration, the lid housingportion rotates approximately ninety degrees to a raised position abovethe main housing portion so that an end user can type inputs whileviewing the display. After usage, convertible information handlingsystems rotate the lid housing portion over the main housing portion toprotect the keyboard and display, thus reducing the system footprint forimproved storage and mobility. Convertible information handling systemscan also include a touchscreen display that accepts end user inputs astouches at information presented by the display.

One tool used to interact with a touchscreen display is a stylus thatwrites like a pen by touching a tip at the touchscreen display. Anadvantage of a stylus, as opposed to a finger, is that a stylus has amore precise input point and mimics conventional pens that write ink topaper. The precision of inputs is provided by a small point of thewriting tip and enhanced by transmitting a signal from the writing tipthat is detected by the touchscreen display, such as a capacitive sensorthat, in essence, detects near field effects. In addition, a stylus canenhance end user inputs through wireless communications with theinformation handling system, such as with BLUETOOTH. As an example, astylus typically includes a push button near the tip than an end usercan activate to change the writing input accepted by the informationhandling system, such as commanding a thicker or thinner drawn line or adifferent color. Other push buttons on the stylus control power andBLUETOOTH connectivity, such as commanding advertising. One difficultywith the inclusion of complex functionality and pressable buttons in astylus is that the stylus housing should mimic a pen or other writingutility with a small round housing and minimal weight. Robustinteractive buttons generally add weight and size to the housing aroundthe button location and at an increased cost. Deploying processingcapabilities in a pen-sized housing can prove difficult and expensive.In addition, the processing capability tends to have increased powerdraw that reduces battery life and can result in selection of largerbattery sizes. One way to address this larger power draw is to sleep thestylus when not in use, however, this often introduces confusion andinconvenience to an end user who has to press a button to wake thestylus or experiences a delay in active inking while the stylus wakes.

Another difficulty that tends to arise with use of an active stylus isarranging to charge the battery. Including a port to interface with acharging cable tends to increase the housing size and impact the stylususability. An alternative charging technique is to place the stylus nextto a wireless charger and communicate charge wirelessly. For example,the stylus may be placed on a wireless charger pad on a desktop next toan information handling system that also receives a wireless charge. Asanother example, a magnet in the stylus may be used to attach the stylusto a side of an information handling system that has a wireless chargerto communicate charge to the stylus. Since a stylus has a round andsmall shape that mimics a pen, a stylus can roll off of charging pad orfall from a magnetic attachment and become lost, such as by rolling awayfrom the end user on the floor so that it is difficult to locate.

SUMMARY OF THE INVENTION

Therefore, a need has arisen for a system and method which supports astylus having input buttons formed in a housing of contiguous material.

A further need exists for a stylus that manages power use with contextderived in part by accelerometer and audio information.

In accordance with the present invention, a system and method areprovided which substantially reduce the disadvantages and problemsassociated with previous methods and systems for assembly of a stylus. Ahousing of contiguous material of a first thickness has inputs definedat portions of a second thickness of a thinner amount of material toflex in response to an end user press. The input buttons couple to asubassembly that slides into an opening of the stylus housing with aspring aligned to the area of reduced material thickness that biases thebutton outward. A magnet coupled to spring presses inward towards amagnetic sensor that detects increased magnetic flux at an input press.

A further improvement to the art is provided by accelerometer andmicrophone monitoring of stylus context to manage power state and stylusbattery discharge. Logic stored in non-transitory memory and executed ona processing resource integrated in the accelerometer monitors foracceleration profiles based upon a static or dynamic environment of thestylus. A microphone monitors for sounds associated with certaincontexts, such as rolling or falling stylus, to supplement the contextdetermination. A variety of power consumption states are applied thatreduce power draw while offering a rapid response of the stylus for enduser inking.

More specifically, a portable information handling system processesinformation with processing components disposed in a planar housing,such as a central processing unit that executes instructions to processinformation and a random access memory that stores the instructions andinformation. A touchscreen display disposed on one side of the planarhousing presents the information as visual images and accepts touches asinputs. A stylus having a writing tip exposed at one end of acylindrical housing provides touch inputs at the touchscreen display ina manner that mimics a pen and with an active tip that enhancescapacitive touch detection. The stylus has a single shot plastic housingformed as a cylinder with a writing tip opening at a first end and anend cap opening at an opposing second end. A subassembly with a circuitboard, a writing tip and an end cap slides into the housing at thesecond end to expose the writing tip at the first end and enclose thecircuit board with the end cap at the second end. The circuit boardincludes first and second input buttons that align with portions of thehousing having a reduced thickness with a leaf spring of each inputbutton pressing outward at the area of reduced thickness so that aninput press flexes the housing material inward to push the leaf springtowards the circuit board. A magnet coupled to the leaf spring hascloser proximity to a magnetic sensor, such as magnetometer or Hallsensor, when a press is made at the input button so that an input isdetected at the circuit board. The circuit board has a main processingresource, such as an MCU, an accelerometer and an audio processorinterfaced with a microphone. The accelerometer applies accelerationprofiles using an integrated processing resource to manage power, suchas waking and sleeping the main processing resource and radio based upondetected accelerations and other context monitored with theaccelerometer processing resource while the main processing resource andthe radio sleep. Similarly, the microphone applies audible profiles,such as the sound of a rolling stylus or a stylus to ground impact, tomonitor a context of the stylus. Wake times for the main processingresource and wake events may be managed by GPIO commands from theaccelerometer and/or microphone so that the main processing resource cananalyze context when awake and reset the acceleration and sound profilesused by the accelerometer processing resource when the main processingresource sleeps.

The present invention provides a number of important technicaladvantages. One example of an important technical advantage is that aninformation handling system stylus assembles a subassembly into ahousing with a simple sliding motion to have input buttons of thesubassembly aligned with thin material portions of the housing. The thinmaterial flexes slightly to provide an input signal by pressing a magnettowards a magnetic sensor with minimal wear on the housing material overtime, thus providing a simple, reliable and robust input button. Thestylus manages power draw in an efficient manner by reference toacceleration and audio profiles associated with contexts havingpredictable behaviors. For example, a static environment with feweraccelerations might minimize power draw in an idle state by relying onlyon logic executing in a processing resource of an accelerometer while adynamic environment might use more frequent wakes to analyze context andreset the acceleration and audio profiles. This provides minimal batterydraw yet offers rapid response in the event of an end user initiatinguse of the stylus to ink on a touchscreen display.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be better understood, and its numerousobjects, features and advantages made apparent to those skilled in theart by referencing the accompanying drawings. The use of the samereference number throughout the several figures designates a like orsimilar element.

FIG. 1 depicts an exploded perspective view of a portable informationhandling system and stylus;

FIG. 2 depicts a front perspective view of the stylus;

FIGS. 2A and 2B depict side cutaway views of the stylus configured toaccept inputs at an input button;

FIG. 3 depicts an exploded view of the stylus and a subassemblyconfigured to slide into the stylus;

FIG. 4 depicts a flow diagram of a process to manage an input press atthe stylus button;

FIG. 5 depicts a flow diagram of a process to manage release of an inputbutton at the stylus;

FIG. 6 depicts a variety of acceleration profiles associated with stylusmovement and detected by an accelerometer in conjunction with othercontext;

FIG. 7 depicts a flow diagram of a process for managing stylus powerbased upon acceleration profiles and context;

FIGS. 8A and 8B depict examples of sound monitoring with a stylusmicrophone to detect stylus context; and

FIG. 9 depicts a flow diagram of a process for managing stylus power andposition reporting based upon microphone and acceleration detection ofvarious contexts.

DETAILED DESCRIPTION

A portable information handling system stylus has a durable structurewith integral input buttons coupled to a subassembly and interactingthrough a thin housing portion, along with battery power managementthrough acceleration and sound context. For purposes of this disclosure,an information handling system may include any instrumentality oraggregate of instrumentalities operable to compute, classify, process,transmit, receive, retrieve, originate, switch, store, display,manifest, detect, record, reproduce, handle, or utilize any form ofinformation, intelligence, or data for business, scientific, control, orother purposes. For example, an information handling system may be apersonal computer, a network storage device, or any other suitabledevice and may vary in size, shape, performance, functionality, andprice. The information handling system may include random access memory(RAM), one or more processing resources such as a central processingunit (CPU) or hardware or software control logic, ROM, and/or othertypes of nonvolatile memory. Additional components of the informationhandling system may include one or more disk drives, one or more networkports for communicating with external devices as well as various inputand output (I/O) devices, such as a keyboard, a mouse, and a videodisplay. The information handling system may also include one or morebuses operable to transmit communications between the various hardwarecomponents.

Referring now to FIG. 1 , an exploded perspective view depicts aportable information handling system 10 and a stylus 28. Portableinformation handling system 10 is built in a planar housing 12 having atouchscreen display 14 coupled on one side and exposed to accept touchinputs by an end user. A motherboard 16 couples within housing 12 tointerface processing components that cooperate to process information.For instance, in the example embodiment, a central processing unit (CPU)18 executes instructions to process information in cooperation with arandom access memory (RAM) 20 that stores the information andinstructions. A solid state drive (SSD) 22 has non-transitory memorythat stores the information and instructions during power down, such asan operating system that is retrieved to RAM 20 at system boot. Anembedded controller 24 manages physical interactions between components,such as with application of power and management of thermal constraints.Embedded controller 24 supports interactions by CPU 18 with input/output(I/O) devices, such a keyboard, mouse and the touch controller oftouchscreen display 14 that reports touch inputs. A wireless networkinterface controller (WNIC) 26 provides wireless signal communicationwith external devices, such as through WiFi and Bluetooth protocols.

Stylus 28 has a writing tip 30 extending from one end of a cylindricalhousing that mimics a pen. Writing tip 30 provides a more precise pointof contact at touchscreen display 14 than is available by a finger touchso that end user inputs can include writing and drawing as if on a pieceof paper. In the example embodiment, writing tip 30 has enhanced touchinput accuracy by outputting a signal generated from internal componentsthat improve capacitance touch detection. The signal from writing tip 30is generated with a battery included in stylus 28 that is periodicallycharged and managed by touch buttons on stylus 28 that exchange wirelesscommands with information handling system 10. For example, stylus 28 hasa power button that also commands Bluetooth functions, such as pairing,and an inking button that allows an end user to control line width, asan example, with touch inputs at stylus 28 that are communicated toinformation handling system 10. In the example embodiment, stylus 28 hasa magnetic “garage” located at one side of housing 12 so that magneticattraction holds stylus 28 in place when not in use. A wireless chargernear the garage provides a wireless power charge to stylus 28 to chargeits internal battery when garaged. In this manner, stylus 28 is readyfor an end user to grasp and use as desired with a full charge availableto perform active capacitive writes from writing tip 30.

Referring now to FIG. 2 , a front perspective view depicts the stylus28. Stylus 28 is built in a cylindrical housing having a writing tipopening at one end through which writing tip 30 extends and an end capopening at an opposing end that is covered by an end cap, as describedin greater detail below. A first input button 32 is located proximatewriting tip 30, and a second input button 34 is located at the endopposite writing tip 30. In various embodiments, each input button mayhave different controls for stylus 28, such as adjusting inking widthand/or color, turning power on and off, and managing Bluetoothadvertising and pairing. In the example embodiment, stylus 28 has acylindrical shape that includes a partially flat surface that restsagainst the information handling system housing when garaged.Alternative embodiments may include additional input buttons andalterations to the shape, although generally a cylindrical shape thatmimics a pen, as depicted, tends to meet end user expectations forwriting at a touchscreen display. In the example embodiment, inputbuttons 32 and 34 are manufactured contiguous with the rest of thestylus housing as a thinner material, such as with a single shotinjection mold of plastic that defines a first material thickness forthe housing and a second material thickness for the input buttons thatis less than the first material thickness. The thinner materialthickness at input buttons 32 and 34 flexes in response to a press topass an end user input to an input button assembly within the stylushousing, such as is described below in greater depth.

Referring now to FIGS. 2A and 2B, side cutaway views depict the stylusconfigured to accept inputs at an input button as indicated by thecross-sectional lines of FIG. 2 . FIG. 2A depicts a cross-sectional viewof input button 34 having a thin-walled section 36 at which an end userpress flexes the housing material inward and against a leaf spring 38biasing device. Leaf spring 38 couples to a circuit board 44 underthin-walled section 36 to press upward against thin-walled section 36for support to a neutral position when not pressed by an end user. Thisupward bias of leaf spring 38 helps to reduce risk of damage at thethin-walled material due to extraneous contact during normal use. Amagnet 40 couples to a bottom surface of leaf spring 38 alignedvertically over a magnetometer integrated circuit 42 that measuresmagnetic flux, which varies based upon the vertical position of magnet40. Magnetometer integrated circuit 42 may include a variety of sensorsthat detect magnetic fields and flux, such as Hall switch or compass.FIG. 2B depicts a similar arrangement for input button 32 with a leafspring 54 biasing upwards against a thin-walled section of the housingand having a magnet 56 coupled to a lower side over a magnetometer 58coupled to a circuit board 60. In each case, the leaf spring is a thinmetal material, such as stainless steel, assembled to the circuit boardalways have some upward bias working against the thin-walled housingsection so that no air gap exists between the metal material and housingat the upper arc of the leaf spring. In one example embodiment, amagnetometer magnetic sensor detects movements of 0.2 mm with aresolution of 0.01 mm so that relatively small movements flexing thehousing thin-walled section inward can be sensed as an input.

When an end user presses on input button 32 or 34 to flex thethin-walled material inward, a magnetic sensor, such as a magnetometer,detects the change in magnetic flux due to the change in distancebetween the magnetic sensor and magnet, which sends an input signaltrigger to the circuit board. When the end user releases the inputbutton, the leaf spring and magnet return to the biased outward neutralposition so that the magnetic sensor detects reduced magnetic flux andceases the trigger signal to the circuit board. The thin-walled materialat each input button flexes a small but perceptible amount of movementin response to an end user push. The movement is reinforced by theoutward biasing of the leaf spring to provide an end user withadditional feedback that an input has been completed. In FIG. 2A, an LED52 is illuminated to indicate an input as further feedback to the enduser. LED 52 is located below thin-walled material 36 where it extendsover end cap 50 coupled at the end of the stylus housing. In the exampleembodiment, end cap 50 has an opening that allows external sounds toreach a microphone integrated circuit 48, such as a MEMS typemicrophone, that provides detected sounds to an audio integrated circuit46, as is described in greater detail below.

Referring now to FIG. 3 , an exploded view depicts the stylus 28 and asubassembly 64 configured to slide into the stylus housing 62.Subassembly 64 is a structure that holds one or more circuit boards 44ready to assemble into housing 62. Housing 62 is a body of contiguousmaterial manufactured with a single shot of plastic material havingthinner material at input buttons 32 and 34. In the example embodiment,the location of input buttons 32 and 34 are highlighted with a slightindent in the exterior surface to help an end user see and feel thelocation of the input buttons. Input button 34 extends past the end ofhousing 62 at the end cap opening to overlap end cap 50 when subassembly64 inserts into housing 62 with writing tip 30 in the end cap opening,as depicted. Subassembly 64 includes leaf springs 38 and 54 built inlocations to align with the thinner material of housing 62 at inputsbuttons 34 and 32 respectively. A processing resource 66 coupled tocircuit board 44 provides processing functions, such as execution ofinstructions to control stylus functions and radio communications, suchas with a radio system on chip (SOC) solution. An accelerometer 68senses accelerations, such with a three axis gyroscope configuration.When subassembly 64 fully inserts into housing 62, end cap 50 engageswith the inner circumference of housing 62 to hold subassembly 64 inposition so that writing tip 30 extends out the writing tip opening inpositions to support stylus writing. In one example embodiment, end cap50 may be held in place with additional coupling devices, such as screwor adhesive.

Referring now to FIG. 4 , a flow diagram depicts a process to manage aninput press at the stylus. The process starts at step 70 with a fingeror thumb press at an input button defined by an area of reduced materialthickness in a contiguous material housing body. At step 72 thethin-walled portion of the housing flexes inward in response to the enduser press. At step 74, the metal spring biasing outward at the innerside of the thin-walled housing portion is overcome to move inward.Although the example embodiment depicts a leaf spring, other types ofsprings or biasing devices may be used to bias outward at thethin-walled portion and change the position of the magnet in response toan end user press. At step 76, the magnet mounted on the leaf springmoves inward with the leaf spring and towards the magnetometerintegrated circuit to increase the magnetic flux in proximity to themagnetometer. At step 78, the magnetometer integrated circuit detectsthe increased magnetic flux strength when the magnet moves in closerproximity. As is described above, other types of magnetic sensors may beused such as a Hall sensor. At step 80, when the detected magnet fluxexceeds a defined limit an input trigger command is provided to thestylus circuit board and processing resource, such as to start adebounce timer that validates the input.

Referring now to FIG. 5 , a flow diagram depicts a process to managerelease of an input button at the stylus. At step 82 the end user fingeror thumb releases pressure at the input button thin-walled section. Atstep 84, the leaf spring biases the thin-walled portion outward to theneutral position. At step 86 the leaf spring returns to the neutralposition, raising the magnet at the bottom side of the leaf spring awayfrom the magnetometer. At step 88 the magnet mounted on the bottom sideof the leaf spring is raised and moved out of proximity to themagnetometer to reduce the magnetic flux below the strength associatedwith detection of the input. At step 90, the magnetometer detectsreduction of the magnetic flux strength when the magnet moves apredetermined distance from the magnetometer. At step 92, themagnetometer integrated circuit responds to the reduced magnetic flux bysending a command to the circuit board and processing resource, such asa GPIO debounce signal that completes a timer detecting whether theinput button press was sufficient to command an input. In one exampleembodiment, completion of an input may command illumination of an LED,such as the LED located at the end cap.

Referring now to FIG. 6 , a variety of acceleration profiles aredepicted that are associated with stylus movement and detected by anaccelerometer in conjunction with other context. The stylus storesacceleration profiles associated with the different contexts innon-transitory memory, such as flash memory integrated in anaccelerometer, and compares the sensed accelerations against theacceleration profiles, as shown by the example sensed acceleration axes108, to manage a power consumption state of the stylus so that stylusbattery life is enhanced. As an example, stylus power is consumed in anactive state by writing tip active inking at approximately 100 to 150microamps, by a Bluetooth processing resource, such as a SOC, in an idlemode at approximately 10 to 20 microamps and by an accelerometer at 8 to9 microamps. In the example embodiment, a processing resource andnon-transitory memory of the accelerometer execute logic that monitorsthe acceleration profiles so that the main processing resource andinking resources can sleep or even have power cutoff to avoid all powerdissipation when the stylus is not in use. For instance, the stylusaccelerations are tracked in x, y and z axes and compared against theacceleration profiles to determine when and how the main processingresource and inking are powered. In the static pen test 100, a lack ofaccelerations confirms the sleep state so that only accelerometer poweris applied and the accelerometer logic may monitor for movement atincreased time intervals. In the pen attached to stylus state 102, aconfirmation of the stylus in a garaged position is an indication of acontext associated with non-use of the stylus. The garaged state may beconfirmed by detection of a charge applied to the stylus, such as withwireless charging, or a proximity detected with a magnet in theinformation handling system in proximity to a Hall sensor of the stylus.Alternatively, a physical switch or physical coupling of the stylus tothe information handling system may indicate the garage state. Inaddition, the garage state may include a coupling to a differentphysical device rather than just an information handling system, such asa pocket protector or carrying case. A pen in a bag acceleration profile104 may include acceleration patterns that mimic a person walking orthat match the acceleration of an information handling system in the bageven though the stylus is not garaged. The fiddling with the pen profile106 has random accelerations that are small time intervals associatedwith end user touches at the stylus. During such active profiles, thestylus main processing resource may be commanded active to monitorstylus power consumption and more rapidly respond to end user stylusinteractions, such as by commanding inking to be activated when writing.

As an example, use of acceleration profiles, management of stylus powerstates is shifted between logic executing on the accelerometerprocessing resource and the main processing resource based upon sensedaccelerations and other context. When a stylus rests without anymovement for an extend time period, such as on a desktop for greaterthan a minute, power to all components other than the accelerometer maybe cut off completely, such as with a hard off switch managed by theaccelerometer, so that only the accelerometer consumes power. In thisacceleration profile, logic stored in a non-transitory memory of theaccelerometer executes on a processing resource integrated in theaccelerometer to monitor for stylus movement and, in the meanwhile,manage a minimum power consumption. When movement is detected, thestylus may wake to a standby power state that provides main processingresource functions to perform a greater analysis of context or theaccelerometer processing resource may be used until an end user activestate is deemed appropriate. In some situations, a lack of movement foran extended time period may result in the accelerometer commanding ahard off by cutting off power draw from the battery, although this powerstate will generally need recovery by an end user input, such aspressing a power button.

Once the accelerometer detects motion to wake the stylus from the sleepstate, the context is determined and applied to manage power at thestylus. In one example embodiment, the context is broken into a staticenvironment and a dynamic environment. In a static environment, such aswhen the stylus rests on a desktop surface, the stylus sleeps withaccelerator-only monitoring until motion is detected. When motion isdetected, the stylus comes to a full active state with the mainprocessor and inking active, and monitors for normal use for a oneminute period, such as touches at the writing tip and accelerationsassociated with end user writing with or handling of the stylus. Thestylus remains awake until the context indicates a static environmentand no accelerations are detected for one minute, after which the stylussleeps again in an accelerometer-only monitoring mode. In a dynamicenvironment, accelerations are detected without actual use of the stylusin an active write mode, such as detection of inking by the writing tip.As an example, an end user fiddling with the stylus or packing thestylus in a backpack where it bounces around will create a good numberof accelerations not associated with normal use. In such a dynamicsituation, extending battery life of the stylus relies upon discernmentof situations that will result in active stylus inking. Further,anticipating active stylus inking provides a rapid response so that thestylus is prepared to write when the end user desires to write. In adynamic environment with accelerator-only monitoring, at initialdetection of an acceleration the stylus is woke to a standby state asabove and a check is made to determine if the stylus is garaged, such asby checking to determine if a wireless charger is present. When thestylus is garaged, dynamic accelerations that match a walking profilemay indicate that the stylus is in a backpack so that the stylus maywake less frequently to check for use, thus reducing power consumptionand allowing logic of the accelerometer integrated processing resourceto manage power. Although the example embodiment wakes to a full standbystate to use the main processing resource to determine if the stylus isgaraged, in an alternative embodiment a GPIO from a charger or a Hallsensor directly to the accelerometer may be used so that theaccelerometer logic can determine whether the stylus is garaged withoutwaking the main processing resource.

In a dynamic environment, when a garaged status is not detected, thestylus applies logic in an accelerometer only mode that helps tomaintain reduced power consumption where the stylus is not in active useyet remain available to quickly respond when an end user initiatesinking. If the stylus is not garaged, an initial standby state iscommanded with the main processing resource active to analyze motion,such as identifying an acceleration profile associated with walking orfidgeting. If any context indicates active use of the stylus by an enduser, such as pressure on the writing tip or button presses, the stylusremains in the standby state ready to initiate inking. In the dynamicenvironment with a context of active use, the stylus may apply morefrequent checks in the standby state to detect active use beforecommanding a sleep state after a predetermined time. If a predeterminedtime passes without context indicating inking by an end user, the stylussets a “shaking” bit of the accelerometer to indicate a dynamicenvironment and then commands a standby mode with accelerometer onlymonitoring. When the shaking bit is set, a variety of wake logics may beapplied based upon the context at the time that the shaking bit is set,such as a walking profile or a fiddling profile. In one exampleembodiment, a wake interval of three seconds is set in the dynamicenvironment to check for active use and then monitoring withaccelerometer only is commanded. Other intervals and types of monitoringmay be used, such as by setting the dynamic environment accelerationprofile in the accelerometer and monitoring with the accelerometer onlyunless a change in the acceleration profile is detected, such as walkingchanging to rest. At the detection of a change of the accelerationprofile by the accelerometer logic, a wake of the stylus main resourcemay be performed to determine the context and reset the type ofacceleration profile monitored by the accelerometer only logic. In thisway, monitoring by the accelerometer detects changes to the accelerationprofile with a low power consumption and wakes the main processingresource to reprogram the accelerometer for the next accelerationprofile to monitor so that power consumption is reduced while styluscontext is monitored with greater accuracy.

Referring now to FIG. 7 , a flow diagram depicts a process for managingstylus power based upon acceleration profiles and context. The processstarts at step 110 with the stylus in a shut down state except formonitoring by logic executing on a processing resource integrated in theaccelerometer. At step 112 a determination is made of whether the stylusis shaking and, if no accelerations of at least a predetermined minimumare detected, the process returns to step 110 to continue in the shutdown state. If accelerations are detected at step 112, the processcontinues to step 114 to wake pen functions all on in a sleep state, forexample by waking the main processor while sleeping the ink function,and to step 116 to determine if the stylus is attached to a tabletinformation handling system or otherwise garaged. When the stylus isgaraged, the logic assumes a static environment of nonuse and, at step118 monitors the context to confirm the nonuse. At step 120 afternonuse, the stylus enters the shut down state with monitoring performedby logic executed on the accelerometer processing resource with logicstored in non-transitory memory accessible by the accelerometerprocessing resource. During the ten seconds of monitoring, the stylusmain processing resource may program the context and monitoring logicapplicable to the accelerometer processing resource. For instance, thewake interval for a garaged stylus may be increased so that powerconsumption is reduced and the logic may simply check to confirm agarage status at each wake so that a minimal power consumption is useduntil the stylus leaves the garaged status, at which time accelerationsmay be monitored or a wake to reprogram the context may be performed.

If at step 116 the stylus is not garaged, such as with attachment to thetablet information handling system, the process continues to step 122 towake the stylus functions in a sleep state. For example, the stylus mainprocessing resource and radio wake to check the stylus context, such asthe presence of a tablet information handling system radio or a press bythe writing tip on a touchscreen display. At step 124, if the stylusdoes not have a context of active use, such as inking, the processcontinues to step 126 to determine if a “shaking” bit of the stylus isset to zero. The shaking bit indicates whether the stylus has been in asleep mode with a static or dynamic environment. If the shaking bit isset to one, the process continues to step 128 to power down the stylusfor three seconds and then return to step 110 to continue monitoring foractive use. The wake interval of three seconds with monitoring only bythe accelerometer provides a minimal drain on battery charge andsufficient monitoring that will capture a change in context to an activeuser state so that the stylus is prepared for use when an end userstarts inking. If at step 126 the shaking bit is set to zero, theprocess continues to step 142 to sleep the stylus for three seconds toensure the dynamic environment nonuse state, and then the shaking bit isset to one at step 144. At step 146 the stylus is placed in the shutdown state so that monitoring continues at step 110 with the shaking bitset at one.

If at step 124 the stylus wakes to detect a context of end userengagement with inking functions, the process continues to step 130 in afull wake state to support active use and continues monitoring activeuse at step 124 until stylus activity has ended. When at step 130 thestylus context indicates that stylus use is complete, such as completionof inking and a predetermined amount of time without accelerations ordetection of a garaged status, the process continues to step 132 tofirst confirm completion of functional use with five seconds of noaccelerations and then to step 134 to sleep the stylus with theaccelerometer monitoring for accelerations. At step 136 the stylus ismonitored for acceleration for thirty seconds, returning to step 124until the timer indicates completion of the monitoring. If steps 124through 134 complete for thirty seconds without further functional useof the stylus, then at step 136 the process continues to step 138 withthe stylus transition to a shut down state and step 140 with theaccelerometer shake bit set to zero, indicating a static environment inthe shutdown state.

Referring now to FIGS. 8A and 8B, examples depict sound monitoring witha stylus microphone to detect stylus context. The microphone in stylusprovides additional information regarding context to help manage powerconsumption and to track stylus position and availability to an enduser. FIG. 8A depicts an example pen drop acceleration profile 150 inwhich a stylus drops and impacts a floor creating an impact noise. Thepen drop profile is detectable both by a freefall detection of theaccelerometer and the impact acceleration. The accelerometer may wakethe stylus main processing resource through a GPIO input at detection offreefall or impact accelerations. In addition, the accelerometer maywake the microphone so that the sound of the impact is detected and anindication of the impact is radio communicated back to the tabletinformation handling system, thus allowing the system to track thelocation at which the impact occurred. In addition, orientationdetermined by the accelerometer may be captured at the impact todetermine if the stylus writing tip sustained the force of the impact,such as when the writing tip is oriented downward at the time of theimpact. FIG. 8B depicts an example pen rolling off acceleration profile152 in which a stylus rolls on a desktop surface to generate a rollingsound picked up by the microphone. In both the impact and the rollingscenarios, the microphone may be used to detect the context with orwithout the accelerometer. For instance, the microphone may monitorsounds in a low power mode with an integrated processing resource thatwakes the rest of the stylus if a detected sound matches an impact orrolling sound pattern. Alternatively, the accelerometer may wake themicrophone when a freefall or a rolling acceleration profile is detectedto help confirm the context of the stylus. In alternative embodiments,other types of sounds may be monitored by the microphone to determinethe stylus context, such as the sound of typing as an indication of enduser engagement with an information handling system, the sound ofmultiple voices to indicate a multiperson conversation, such as mayindicate sharing of a tablet view and anticipated stylus use, or thesound of one voice to indicate a telephone conversation.

Referring now to FIG. 9 , a flow diagram depicts a process for managingstylus power and position reporting based upon microphone andacceleration detection of various contexts. The process starts at step176 with the stylus rolling across an uneven surface, such as a desktop.At step 178, the sound generated by the rolling stylus is detected bythe stylus microphone. Note that the microphone may monitor for thesound with the stylus in a sleep state, may be awakened by theaccelerometer or may detect the rolling sound during normal use. At step180, an artificial intelligence DSP of the microphone or its audioprocessor process the sound characteristics to determine the rollingsound. At step 182, the accelerometer in the stylus detects the changesin orientation due to rolling, such as with a gyroscope defined byaccelerations detected with accelerometers aligned along three axes. Atstep 184, the stylus main processing resource processes both the audioand acceleration data to determine the context of the stylus as rollingon a desktop surface. In response to the detected context, at step 186the main processing resource commands communication by Bluetooth radioto the tablet information handling system. At step 188, the Bluetoothlogic on the tablet information handling system communicates to anapplication of the information handling system regarding the styluscontext so that the position of the system can be stored and the enduser can be alerted to the unstable position of the stylus.

At step 190 of the example embodiment, the stylus continues to rolluntil it falls from the desktop. As an alternative, at step 160, the penmay accidentally detach from a garaged state at the tablet informationhandling system to fall without first rolling on the desktop surface. Inboth embodiments, at step 160 a freefall acceleration state may bedetected at the accelerometer and communicated by Bluetooth to thetablet information handling system. Further, the freefall state maygenerate a GPIO signal to wake the stylus so that the main processingresource, such as an MCU, is available to process context information.At step 162 the stylus hits the floor with a resulting change from afreefall acceleration state to a high g-force reading and an impact thatcreates an impact sound. At step 164 the impact sound generated by thestylus hitting the floor is captured by the microphone and stored inlocal memory. At step 166, an audio artificial intelligence DSPprocesses the sound captured by the microphone and analyzes thecharacteristics to determine that the sound is the stylus striking ahard surface. At step 168, the accelerometer of the stylus picks up andstores acceleration and orientation information while the stylus is infreefall and at impact. At step 170 the stylus processing resourceanalyzes both the acceleration and audio information to determine thatthe stylus has fallen to the floor and the orientation of the stylus atimpact. As an example, an orientation at impact of the writing tip downcan indicate a risk of damage to the writing tip so that the stylus canprovide a message to the tablet information handling system regardingthis risk. At step 172 the stylus processing resource communicates amessage to the Bluetooth radio regarding the stylus event. At step 174,the Bluetooth radio communicates to the tablet information handlingsystem to report the stylus falling event so that the system can trackthe position at which the fall took place and any potential damage basedupon the orientation of the stylus at impact.

Although the present invention has been described in detail, it shouldbe understood that various changes, substitutions and alterations can bemade hereto without departing from the spirit and scope of the inventionas defined by the appended claims.

1. An information handling system comprising: a housing; a processordisposed in the housing and operable to execute instructions thatprocess information; a memory disposed in the housing and interfacedwith the processor, the memory operable to store the instructions andinformation; a display coupled to the housing and having a touchscreeninterfaced with the processor to detect touch inputs; and a stylusseparate from the housing having a cylindrical housing with a writingtip extending from one end, the cylindrical housing having a material ofa first thickness and having a button contiguous with the material anddefined by the material of a second thickness of less than the firstthickness.
 2. The information handling system of claim 1 furthercomprising: a spring disposed in the housing at the button and biasingthe button outward; and a sensor disposed under the button to detect aninward press at the button.
 3. The information handling system of claim2 wherein the spring comprises a leaf spring disposed over the sensor.4. The information handling system of claim 3 further comprising: amagnet coupled to the leaf spring; wherein the sensor comprises amagnetometer operable to detect increased magnetic flux at a buttonpress, the button press overcoming the leaf spring biasing to bring themagnet in closer proximity to the magnetometer.
 5. The informationhandling system of claim 4 further comprising first and second of thebutton, the first located proximate the writing tip, the second locatedat an end opposite the writing tip.
 6. The information handling systemof claim 4 wherein the cylindrical housing comprises a single shotplastic material having a writing tip opening at a first end sized tofit through the writing tip and an end cap opening at a second endopposite the writing tip.
 7. The information handling system of claim 6further comprising: a circuit board; a processing resource coupled tothe circuit board and interfaced with the sensor to detect buttonpresses; and a subassembly tray coupled to the circuit board and sizedto slide into the cylindrical housing with the writing tip at a firstend and an end cap at an opposing second end.
 8. The informationhandling system of claim 7 wherein the button is located at the secondend, extending past the second end to overlap the end cap.
 9. Theinformation handling system of claim 8 further comprising: a lightcoupled to the subassembly tray to align under the button at theoverlap.
 10. A method for performing inputs at a stylus, the methodcomprising: forming the stylus housing and button with a contiguousmaterial having a reduced thickness at the button; applying a bias fromwithin the housing outward at the button; and sensing a press at thebutton inward to the housing that overcomes the bias.
 11. The method ofclaim 10 further comprising: applying the bias with a leaf springpressing upward at a central location of the button; and detecting thebutton press based upon an inward movement of the leaf spring.
 12. Themethod of claim 11 further comprising: coupling a magnet to the leafspring; and detecting the press at the button with a magnetometerdisposed in the stylus housing proximate the magnet.
 13. The method ofclaim 12 further comprising: coupling an end cap at one end of thestylus housing; and extending the button having the reduced materialthickness past the one end of the stylus housing to overlap the end cap.14. The method of claim 13 further comprising illuminating a light underthe button at the overlap.
 15. The method of claim 12 furthercomprising: extending a writing tip from an opening at one end of thestylus housing; and forming the button proximate the writing tip. 16.The method of claim 15 further comprising forming the stylus housingwith a single shot plastic injection molding to have body of contiguousmaterial between the opening for the writing tip and an end cap openingat an opposing end.
 17. A stylus comprising: a housing of contiguousmaterial between a writing tip opening at a first end and an end capopening at an opposing second end, the material defining an input buttonwith an area of reduced thickness of the contiguous material; and a leafspring disposed in the housing under the button to apply an outwardbiasing force at the button.
 18. The stylus of claim 17 furthercomprising: a magnet coupled to the leaf spring; and a magnetic sensordisposed under the magnet and operable to detect a press at the button,the press bringing the magnet in closer proximity to the magneticsensor.
 19. The stylus of claim 18 further comprising: an end capcoupled over the end cap opening at the second end; wherein the inputbutton area of reduced thickness overlaps the end cap to extend over aportion of the end cap.
 20. The stylus of claim 19 further comprising alight aligned under the input button at the overlap.